NFSv4: Add support for the NFSv4.2 "change_attr_type" attribute

The change_attr_type allows the server to provide a description of how
the change attribute will behave. This again will allow the client to
optimise its behaviour w.r.t. attribute revalidation.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

include/linux/nfs_xdr.h

@@ -152,6 +152,8 @@ struct nfs_fsinfo {
 	__u32			layouttype[NFS_MAX_LAYOUT_TYPES]; /* supported pnfs layout driver */
 	__u32			blksize; /* preferred pnfs io block size */
 	__u32			clone_blksize; /* granularity of a CLONE operation */
+	enum nfs4_change_attr_type
+				change_attr_type; /* Info about change attr */
 	__u32			xattr_support; /* User xattrs supported */
 };